We may be close to a “tipping point” where the weight of evidence against arthroscopic knee surgery for pain is enough to overcome concerns about the quality of studies, bias and vested interests, an expert says.

Writing in an editorial in the BMJ Professor Andy Carr from Oxford University said it was difficult to support or justify a procedure with the potential for serious harm, even if it is rare, when that procedure offers patients no more benefit than placebo.

He was commenting on the results of a meta-analysis of 18 studies on the benefits and harms of arthroscopic surgery compared with a variety of treatments for middle aged and older people with persistent knee pain.

Overall, surgery was associated with a small but significant effect on pain at three and six months (but did not continue) compared with control treatments. No significant benefit on physical function was found, the study published in the same edition of the BMJ found.

A further nine studies reporting on harms found that, although rare, deep vein thrombosis (DVT) was the most frequently reported adverse event, followed by infection, pulmonary embolism and death.

“Interventions that include arthroscopy are associated with a small benefit and with harms,” say the authors, and the benefit is “markedly smaller than that seen from exercise therapy,” wrote the authors from the University of Southern Denmark.

These findings “do not support the practice of arthroscopic surgery as treatment for middle aged or older patients with knee pain with or without signs of osteoarthritis,” they concluded.

When that tipping point is reached “we should expect a swift reversal of established practice,” concluded Professor Carr.